need a quick design for MTM center with P13WH00

[johnmark]

I have a friend (actually my boss0 who wants me to whip up a quick center channel MTM and he wants to use the old Vifa P13WH00 and an aluminum dome in order to match the sound of his mains which use similar drivers.

Not wanting to re-invent the wheel does anyone know of a design like this that used the P13's and a vifa D25AG35 ?

Thanks !

John in Seattle

 

[chrisb]

Before you expend much time or brain power on this project, have you verified that the pair of P13 magnets won't cause problems with the video display?

 

[johnmark]

The center speaker will sit about 2 below a 52" LCD screen

 

[MJL21193]

The center speaker will sit about 2 below a 52" LCD screen

Safe! Only CRT displays are affected by magnets.

 

[chrisb]

the only dumb question is the one that's not spoken

 

[MJL21193]

I have a friend (actually my boss0 who wants me to whip up a quick center channel MTM and he wants to use the old Vifa P13WH00 and an aluminum dome in order to match the sound of his mains which use similar drivers.

Not wanting to re-invent the wheel does anyone know of a design like this that used the P13's and a vifa D25AG35 ?

What you want in a centre speaker is midrange clarity, and these drivers excell at that. A small box will do (~15 litres), small 1.5" port around 4" long should give F3 in the 60Hz range. Bass response is secondary in a centre speaker.

Have fun.

 

[johnmark]

Crossed over at 80-90 hz by his HT receiver will probably get by with a sealed config or maybe to make the enclosure even smaller will try aperiodic (leaky box)

 

[johnmark]

In general, is there a specific crossover order that would promote better lateral response with a sideways MTM ?

 

[augerpro]

In general, is there a specific crossover order that would promote better lateral response with a sideways MTM ?

2.5 way XO will help.

 

[rabbitz]

To maintain tonal balance, base it on the design of his mains, just with a higher F3. A TM may be a better way to go but if power handling and excursion is a problem then MTM or TMM by all means.

 

[rabbitz]

In general, is there a specific crossover order that would promote better lateral response with a sideways MTM ?

Try and put the tweeter as high up as possible with the mid woofers lower (sort of a triangle of drivers). That will help and if he listens on axis it's not an issue anyway.

Here's an example but in a TM.

 

[bjorno]

In my opinion:

....sideways MTM.....

is disastrous for the central dispersion if the T speaker driver is crossed over to high.

b

1(1)

 

[johnmark]

Bjorno,

Because height of the center speaker in this instance will be an issue I don't think the triangle arrangement will be possible. I must limit overall height of the box to 7". This does not leave much space for a tweeter. I would need to use a very compact tweeter and since he wants to use an aluminum dome I am not sure what option I would have if crossing around 1700.

The 2nd plot looks a little bumpy but is within 3db across the necessary width. Do I understand that this is with a mixed order crossover?
Like 3rd order on tweeter and 2nd on the woofers?

John

 

[johnmark]

I was able to use the Passive Crossover Designer and rough out a 3rd order crossover using 2nd order electricals and reverse polarity.
It looks pretty good in a 45 degree horizontal window with the woofers 9" apart.
I can trim the platic faceplate on my Vifa D25AG35 and get this close.

 

[qwad]

hi, dont like to butt in, but l'd take a look at the parts express diy showcase theres a really good mtm centre under the "triune"label in a mini onken style config l just built using a no name korean pr of 130mm shielded drivers and a tonigen tweet all xed over at 2.5k through a simple series x/over a calculator for which can be found on andy graddons "argos"spkr site works really well l'm sure you could acheive a similar result using quality drivers like the vifas you have.... cheers L hope this helps T C



p.s. the vifa tweet you are using can be x/ed over a lot lower as it has an fs of 900 hz l beleive so in theory you could x/ over at around 1800 hz

 

[bjorno]

I was able to use the Passive Crossover Designer and rough out a 3rd order crossover using 2nd order electricals and reverse polarity.

.....

.....

I can trim the platic faceplate on my Vifa D25AG35 and get this close

.....

Yes, An asymmetrical crossover probably does a better job and I think for that case you can lower the frequency to about 1500 Hz and mount the T driver recessed to the same depth as the M drivers are mounted and a total C-C of 187 mm between the M’s.

b

I can trim the platic faceplate on my Vifa D25AG35 and get this close

 

[johngalt47]

any updates on this project?